Inside Macintosh: QuickTime /

Chapter 2 - Movie Toolbox / Movie Toolbox Reference

Functions That Modify Movie Properties / Working With Media Time

SetMediaTimeScale

The SetMediaTimeScale function allows your application to set a media's time scale.

pascal void SetMediaTimeScale (Media theMedia, 
                               TimeScale timeScale);

theMedia

Specifies the media for this operation. Your application obtains this media identifier from such Movie Toolbox functions as NewTrackMedia and GetTrackMedia (described on page 2-138 and page 2-190, respectively).

timeScale

Specifies the media's new time scale.

DESCRIPTION

In response to this request, the Movie Toolbox attempts to adjust the edit list of the appropriate track so that movie playback is unaffected. If you change a media's time scale by setting it to a smaller value, you may lose precision in media time values. In general, you should only increase the time scale value, and you should try to use integer multiples of the existing time scale.

SPECIAL CONSIDERATIONS

Do not use SetMediaTimeScale as a general rule. If you call this function with a number that is not an integer multiple, the duration of the samples vary unpredictably, and their start times tend to drift.

ERROR CODES

invalidMedia

-2008

This media is corrupted or invalid